Tissue penetrating device and methods for using same

ABSTRACT

A device for tissue, especially hard tissue, penetration which incorporated a novel paddle-shaped needle for low friction rotatory penetration of the tissue. A controlled delivery or extraction system is also disclosed for the transfer of material from the device into a tissue site or transfer of material from the tissue site to the device. The delivery system or extraction system includes at least on solenoid or other similar device.

This application is a continuation of U.S. patent application Ser. No.09/757,122 filed Jan. 9, 2001, now U.S. Pat. No. 6,527,778, issued Mar.4, 2003, which is a divisional of U.S. patent application Ser. No.09/033,105 filed Mar. 2, 1998, now U.S. Pat. No. 6,183,442, issued Feb.6, 2001.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a device for penetrating tissue anddelivering bioactive agents thereto or extracting biological materialstherefrom.

More particularly, the present invention relates to tissue penetrationdevices for delivering biologically active agents into tissue sites orextracting biological materials from the tissue sites where the deviceincludes specially designed needles for penetrating a tissue site eitherrotationally or non-rotationally and specially designed delivery orextraction devices for controlled delivery of materials into tissuesites or extraction of materials from tissue sites.

2. Description of the Related Art

Accurate and effective tissue penetration and accurate and effectivedelivery of bioactive agents or extraction of biological fluids ormaterial is regime of needle incorporating devices. Several patents havedealt with such needle incorporating devices including the followingU.S. Pat. Nos. 1,523,068, 2,773,500, 2,773,501, 3,788,320, 3,811,442,3,893,445, 4,666,438, 4,787,893, 4,969,870, 5,176,643, 5,271,744, and5,312,364.

Although these patents generally relate to syringe and needle assembliesfor the delivery of material into or extraction of material out of atissue site, there is still a need in the art for new, efficient andcontrolled delivery and extraction devices incorporating new, efficientneedles which reduce penetration time and improve penetration efficiencyinto sensitive tissue sites.

SUMMARY OF THE INVENTION

The present invention provides a device for delivering materials into orextracting materials from tissue sites. The device includes a fluidreservoir, a tissue penetrator or needle detachably engaging a first endof the reservoir and a plunger associated with the reservoir at itssecond end and designed to slidingly engage an interior surface of thereservoir. The device further includes at least one solenoid having ashaft detachably engaging a top of the plunger for moving the plungerwithin the reservoir, a power supply and associated circuitry for supplyelectrical power to the solenoid and at least one switch for controllingthe solenoid. Preferably, the entire assembly is contained within ahousing including a biased retractable tip protector (preferably,disposable) at its distal end having a penetrator. Additional solenoidscan be used to control needle penetration speed and depth or to allowsimultaneous or sequential infusion or removal of materials into or outof a tissue site.

The present invention provides a device for delivering materials into orextracting materials out of tissue sites. The device includes areservoir/solenoid assembly as described above and additionally, a motorassembly for rotating the solenoid/reservoir assembly and at least onecontrol switch with associated circuitry for activating the motor eitherin cooperation with the solenoid or independent from the switches andcircuitry associated with the solenoid. Again, additional solenoids canbe used to control needle penetration speed and depth by pushing againstthe motor assembly coordinated with needle rotation or to allowsimultaneous or sequential infusion or removal of materials into or outof a tissue site.

The present invention also provides a tissue penetrator or needleincluding a hollow tubular member having a first end, a second endhaving a tissue penetrating tip associated therewith and at least oneperforation therein located between a mid point of the hollow member andthe tip end of the hollow member. The tissue penetrating tip includestwo opposed cutting surfaces, each having a cutting edge, two opposednon-cutting surfaces and an opening associated with the tip at or nearthe apex. The hollow member can also include an enlarged region or sealfor creating a seal between the penetrated tissue site and thepenetrator.

This invention also provides a method for delivering material to atissue site including positioning a tissue penetration device asdescribed above in proximity to a tissue site to be penetrated,penetrating the tissue site with the penetrator, and activating thesolenoid to deliver material into the tissue site from the reservoir ofthe penetration device or transfer material from the reservoir to thetissue site.

The present invention also provides a method for extracting materialfrom a tissue site including positioning a tissue penetration device asdescribed above in proximity to a tissue site to be penetrated,penetrating the tissue site with the penetrator, and activating thesolenoid to extract material from the tissue site or transfer materialfrom the tissue site to the reservoir.

This invention also provides a method for delivering material to atissue site including positioning a tissue penetration device asdescribed above in proximity to a tissue site to be penetrated,rotationally penetrating the tissue site with the penetrator, andactivating the solenoid to transfer material from the reservoir to thetissue site.

The present invention also provides a method for extracting materialfrom a tissue site including positioning a tissue penetration device asdescribed above in proximity to a tissue site to be penetrated,rotationally penetrating the tissue site with the penetrator, andactivating the solenoid to transfer material from the tissue site to thereservoir.

DESCRIPTION OF THE DRAWINGS

The invention can be better understood with reference to the followingdetailed description together with the appended illustrative drawings inwhich like elements are numbered the same:

FIG. 1 is a cross-sectional view of a first embodiment of the tissuepenetration device of the present invention;

FIG. 2 is a cross-sectional view of a second embodiment of the tissuepenetration device of the present invention;

FIG. 3 is a schematic diagram of an embodiment of circuitry of thetissue penetration device of FIGS. 2 and 3;

FIG. 4 is a cross-sectional view of a third embodiment of the tissuepenetration device of the present invention;

FIG. 5 is a cross-sectional view of a fourth embodiment of the tissuepenetration device of the present invention;

FIG. 6 is a cross-sectional view of a fifth embodiment of the tissuepenetration device of the present invention;

FIG. 7 is a front plan view of a first embodiment of a tissuepenetration member of the present invention;

FIG. 8 is a side plan view of the member of FIG. 7;

FIG. 9 is a top plan view of a tip of the member of FIG. 7;

FIG. 10 is a front plan view of the tip of FIG. 9;

FIG. 11 is a side plan view of the tip of FIG. 9;

FIG. 12 is a front plan view of a second embodiment of a tissuepenetration member of the present invention;

FIG. 13 is a side plan view of the member of FIG. 12;

FIG. 14 is a top plan view of a tip of the member of FIG. 12;

FIG. 15 is a front plan view of the tip of FIG. 14; and

FIG. 16 is a side plan view of the tip of FIG. 14.

FIG. 17 is a graph depicting penetration time versus bone thickness datafor the tissue penetration device of this invention;

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The inventors have found that a device can be constructed for theefficient and controlled penetration of tissue sites and the subsequentcontrolled introduction of material into or extraction of material froma tissue site, i.e., transferring material into or out of a tissue site.Such a device, although having broad application in all tissuepenetration applications, has special utility in hard tissue penetrationapplications such as bone, cartilage, tendon, ligaments or the like. Thedevices can be used on any animal, but is preferably designed for usewith mammals and especially humans.

The device also allows for protection of health care providers fromaccidental needle pricks, while providing ease of operation and solenoidcontrolled introduction of materials into or extraction of materialsfrom tissues sites. The device also incorporates a specially designedneedle attached to a high speed motor for fast and easy penetration ofhard tissues such as bone, cartilage, tendon, ligaments or the like Thedevice can also be equipped with torque sensors associated with themotor so that the motor will automatically stop needle rotation when agiven change in torque occurs such as when the needle transition frombone to soft tissue. The torque sensor and associated circuitry can alsoactivate the solenoid either immediately after shutting off the motor orafter a delay so that manual adjustments can be made prior to solenoidactivation. Of course, motor power and solenoid power can be manuallycontrolled either cooperatively or independently depending on thecircuitry associated with the device or upon switch selectionsassociated with the circuitry associated with the device.

The present invention discloses a new device and methodology for use inaccurate tissue penetration and delivery of materials (bioactivematerial such as medications, fillers, tags or tracking agents,implants, or the like) into a tissue site or extraction of materials(bodily fluids, biopsies, tissues samples, bone marrow or the like) froma tissue site.

For example in marrow aspiration, the device would be placed on (incontact with) the bone cortex and the tissue penetrator member orneedle, which resides at the device's distal end, would be rotated bythe motor until it penetrates the cortical bone to a pre-determineddepth. The penetration depth can either be adjusted by an adjustabledepth stop or by having the motor sensor automatically shut the motoroff when a turning torque for the needle indicates full penetration ofthe bone cortex (sudden drop in turning torque). At that instance, thesolenoid (or similar electrically activated retraction device) in a“pull” configuration is either manually or automatically activated orpowered up and bone marrow is aspirated into the needle's hollow shaftthrough orifices or perforations in the shaft and/or through an openingin the needle tip. The material travels through the needle and isaccumulated in the device's storage reservoir.

In this example, the penetrator rotates without linear translation orextension with penetration pressure being supplied by the user. Onceappropriate penetration (and thus tip positioning) is achieved, power tothe motor is manually or automatically discontinued and power to thesolenoid is initiated either manually or automatically. The solenoidthen retracts and aspirates (removes) material from the tissue site orpushes out and delivers materials to the tissue site. The device can beeasily fabricated at a low cost.

Applications

The devices of the present invention can be used for a number of medicalapplications, including, without limitation, the following:

1. Intra-joint Fluid Aspiration:

The penetrator or needle of the device is driven into a tissue sitewithout rotation by a solenoid in a push condition (sometime referred toas a “push” solenoid). Once the needle tip is at the desired location, asecond solenoid in a pull condition (sometimes referred to as a “pull”solenoid) is used to aspirate or remove material such as fluid from thetissue site. In this embodiment, the device does not need to have amotor. This embodiment and use of the device allows for extraction ofsynovial fluids, e.g., to quantify the presence of metallo-proteases orother markers of osteoarthritis, of blood or fluids to alleviate jointpressure, blood to perform culture studies or the like.

2. Intra-joint Delivery Device:

Similarly, a “push” solenoid lets the needle penetrate the joint in alinear fashion. Once the desired penetration is accomplished, amechanical stop acts as an electrical switch for a second “push”solenoid, which applies positive pressure on the plunger of the syringe(reservoir) until all of its contents (such as bioactive agents) arereleased (delivered) into the joint. In this embodiment, the device alsodoes not need to have a motor. This embodiment and use of the deviceallows for delivery of anti-inflammatory drugs and/or painkillers (e.g.,lidocaine) or of articular cartilage surface coating fluids (e.g.,hyaluronic acid, anti-arthritic agents) or the like.

3. Intraosseous Delivery of Drugs or Bioactive Agents:

An example is the delivery of drugs, pharmaceuticals, growth factors,etc. inside the marrow cavity of a bone. For example, if a drug needs tobe delivered in the marrow cavity of the antero-medial diaphysealportion of the tibia, or in a tibial metaphysical portion, the device ispositioned perpendicularly on the skin over the region of the bone to bepenetrated. As the user applies some pressure on the device, thepenetrator (preferably a needle of the paddle-tipped hollow needledesign described herein) protrudes from the housing through the septumassociated with the tip protector, cuts through the skin and rests onthe periosteum. The user switches the motor on and the needle penetratesthrough the cortex, until a mechanical stop is reached (say after a 15mm penetration). The mechanical stop then acts as an electrical sensorand/or switch, which selectively turns the motor off and powers up oractivates the solenoid. The solenoid then pushes out and applies acompressive force on the plunger of the syringe. The drug is pushed outthrough the orifices placed on the lateral aspects of the needle and/orthrough the opening in the center of the needle tip. Of course, themotor activation can be controlled by sensors associated with thedevice. One sensor could determine when bone contact has occurred(pressure sensor), while other sensors could determine when a change intorque has occurred which would indicate a transition from a bone typemedium to a soft tissue medium or a less bone-like medium depending onthe nature of the torque sensors.

The devices of the present invention do not depend on developing largemomentum or subsequent impact to achieve penetration as do many priorart devices. The devices of the present invention penetrate bydeveloping large strains locally in bone close to the interface with thecutting edges of the penetrator. As a result, this method completelyeliminates the possibility of fracturing bone as may be the case inmomentum or impact tissue penetration devices. The devices of thepresent invention also allows for proper controlled delivery ofmaterials into a tissue site reducing if not eliminating delivery untila desired penetration is achieved.

Fluid delivery, moreover, does not depend on inertial forces developeddue to impact. Because it is difficult to control the inertial force inthe syringe fluid in momentum-based delivery systems, it is difficult toconsistently deliver the same amount of fluid every time to a giventissue site. In the devices of the present invention, fluid delivery ismuch more controlled making uniform and consistent administration ofmaterials to a tissue site routine. This uniformity and consistency isaccomplished through the use of solenoid (or a similar) deliverysystems, which delivers or extracts the same amount of material everytime because the solenoid uses the same amount of electrical energy andforce profile during administration as opposed to user administration.

4. Intracranial Pressure Release:

In traumatic head injuries, swelling due to fluid adjacent to the brainmay develop which can lead to death or brain damage. Such fluid build upcan be relieved using the devices of the present invention bypenetrating the cranium in the vicinity of the site of injury. Oncepenetration of the cranium is achieved by drilling through the craniumwith the penetrator or needle, the motor automatically stops (this isaccomplished by shutting down the power to the motor when a reduction ofmotor-torque is detected either manually or automatically). Afterdrilling, the needle can be further inserted into the soft tissue insidethe cranium using user-applied force until a desired penetration depthis achieved. A “pull” solenoid can then pull the plunger of the syringethus creating negative pressure that will aspirate the excess fluid intothe reservoir.

5. Intracranial Delivery of Bioactive Agents:

The devices of this invention can also be used to deliver medicationsuch as cancer drugs to brain tumors. As in application 4, the devicepenetrates the cranium and stops immediately when the needle contactsintracranial soft tissue (torque change on the needle). The usercontinues to apply a small compressive force and thus the needle travelsinto the soft tissue. When a desired penetration is achieved, amechanical stop brings the needle to a stop and also closes the solenoidcircuit. A “push” solenoid pushes the plunger of the syringe until allfluid contents of the syringe are delivered inside the tumor. Thisprocess can be adjusted to proceed at any given rate from very fastdelivery to very slow delivery. Although the delivery of anti-canceragents may require fast delivery, the administration of medications toameliorate the adverse effects of brain injuries such as calpaininhibitors or growth promoters may require slow continuousadministration.

6. Marrow Extraction:

The devices of the present invention can also be used to access themarrow cavity of a given bone. Using a “pull” solenoid, we can create avacuum in the syringe which will aspirate a desired amount of marrowfluid. Examples of extraction are: bone marrow is aspirated fortransplantation for cancer patients or marrow is aspirated to obtainmesenchymal stem cells or other cells to be used in cell-basedtransplantation therapies.

7. Spinal Fluid Extraction:

A similar technique as described in 6 above can be used to aspiratespinal fluid. A double solenoid can be used, where one pushes thesyringe into a proper position and another solenoid pulls and thusaspirates the fluid out.

8. Compartment Syndrome:

Similarly, this system can be used to relieve pressure developed in acompartment syndrome.

The devices of the present invention should preferably have a disposabledistal end because the distal surface comes in contact with skin and maybecome contaminated with bodily fluids (e.g., blood) that maypotentially exude through the penetration orifice and carry viral orbacterial infections. The device also is equipped with a septumprotected needle to aid in preventing needle pricks because the needlebefore and after use is protected within the retractable and preferablydisposable tip protector. The device can include custom made batterypacks and chargers preferably waterproof, made of medical gradematerials, and preferably include sensor that will monitor and indicatebattery charge. The devices can have different heads (distal ends) whichallow or permit different needle penetration depth and/or have sensorsto measure needle to tissue pressure. Penetration depth control can beachieved by having mechanical stops on the retractable tip. Needles ofvarious size and gages can be used as well. The device, moreover, can beused to implant small microdevices into tissue sites and even forscrewing threaded bone pins into bone site to repair fractures.

Paddle-Tipped Hollow Needle

The inventors have also found that a new needle tip design can greatlyfacilitate penetration of hard tissue such as bone with reducedancillary bond injury or fracturing. The needle is of a paddle-tippedhollow design. The needle includes two opposing cutting surfaces withcutting edges off the perpendicular and two opposed non-cuttingsurfaces. The needle tip is generally in the form of a quadrilateral(rectangular or parallelogram) with cutting surfaces associated with itsshort sides and non-cutting surfaces associated its long sides. The tiphas a first interior angle that is generally less than 90° (rectangular)and greater than about 0° (linear) and a second interior angle which is180° minus the first angle. Preferably, the first angle is between about80° and about 10°, more particularly the first angle (which is an acuteangle) is between about 80° and about 50°, and especially the firstangle is between about 80° and about 60°, with 70° being particularlypreferred. As shown in the diagrams (FIGS. 9 and 14), this needle has ashape that allows it to act as a drill bit and thus penetrate bone withease, when rotating clockwise. Of course, a mirror image constructionwould allow the needle to cut in a counterclockwise direction.

The needle design has the following features: (1) the needle designeliminates friction between needle surface and bone, thus, it decreasestime of penetration and thermal damage to the bone; (2) the needle hastwo cutting edges on the two thin sides of flat triangular profiledsurfaces; (3) on the proximal end there is a taper to enlarge thediameter of the needle shaft to match the hole size created by thepaddled bit in order to seal the fluid and prevent leaking on injection(FIG. 12); (4) the needle production will require only a minor change inthe fabrication scheme that is already followed for existing needles.The taper can be an optional, separate piece that can be pressed ontothe shaft of the needle at any position along the length of the shaft;(5) in the intracranial applications, where bone abuts against softtissue, it may be desirable not to use a rotating needle to avoidexcessive soft tissue damage. This can be accomplished by the followingscheme: The needle is powered by the motor which rotates and thus theneedle penetrates the bone. The motor torque (i.e., the resistanceoffered by the bone) is monitored until a sufficiently large drop isobserved. At that point, the distal end of the needle has drilledthrough the bone such as the cranium and about to enter soft tissue. Atthat point, the motor is automatically turned off and through a simplepush by the user the needle can now continue its penetration in a linearmanner (i.e., without rotation). This linear translation continues untilthe mechanical stop is reached at which point the “pull” or “push”solenoid pushes or pulls the syringe plunger and thus delivers oraspirates fluids.

Referring now to FIG. 1, a first embodiment of a tissue penetrationdevice of the present invention, generally 10, is shown. The deviceincludes a housing 12 which can be made of any medical approvedmaterial, but is generally made of a medically approved plastic. Thehousing 12 can be of a generally cylindrical shape or can be shaped toconform to a users hand. Of course, any shape is acceptable, providedthat the shape does not significantly adversely affect the function ofthe device. It should be recognized, moreover, that the housing can beconstructed out of a single material or a mixture of materials, can bean integral structure or can be constructed of detachable elements aswell be described more fully herein.

The device 10 further includes a retractable cap 14 which slidinglyengages an interior surface 16 of housing 12 at its distal end 18. Thecap 14 is biased by a bias member 20 which has a first end 22 associatedwith the cap 14 and a second end 24 associated with a contact switch 26for initiating fluid ejection. The cap 14 also includes a useradjustable depth stop 28 and a needle penetrable membrane 30 associatedwith its bottom surface 32 which is placed in contact with a patientduring use.

The device 10 further includes a needle 34 positioned with in the device10 so that its tip 36 is poised to penetrate the membrane 30. The needle34 is detachably or fixedly attached to a needle holder 38 at itsopposite end 40. The holder 38 is associated with a fluid reservoir 42and forms the reservoir's needle end 44. The reservoir 42 has a plunger46 which slidingly engages an interior surface 48 of the reservoir 42.The plunger 46 acts to either force fluid out of the reservoir or suckfluid into the reservoir depending on whether the device is being usedto delivery material to a tissue site or withdraw material from a tissuesite.

The device 10 further includes a solenoid 50, an electrical contactbushing 52, a bearing 54, a solenoid/needle coupler 56 and a solenoidshaft 58. The shaft 58 has a distal end 60 is either fixedly ordetactably attached to or associated with a top of the plunger 46 sothat the plunger 46 can be moved vertically within the reservoir 42. Ifthe shaft 58 is fully extended prior to use, then the solenoid 50 willretract the shaft 58 and the device 10 will act to remove material fromthe tissue site. If the shaft 58 is fully retracted, then the solenoid50 will extend the shaft 58 and the device 10 will act to injectmaterial into the tissue site. The coupler 56 has a lip 62 that contactsa top edge 64 of the reservoir 42. The lip 62 allows the reservoir 42and associated needle assembly to be pushed downward so that needlepenetration can be controlled by the solenoid 50 instead of beingcontrolled manually. Of course, the depth and rate of penetration aswell as the rate to removal can be manually controlled or controlled bya second solenoid (not shown).

The device 10 further includes a high speed DC motor 66 and amotor/solenoid coupler 68. The motor allows the entiresolenoid/reservoir/needle assembly to be rotated so that the needle candrill into hard tissues such as bone. The bearing 54 is positionedwithin a groove 70 in the housing 12 so that thesolenoid/reservoir/needle assembly can be rotated relative to thehousing 12.

The device 10 further includes an on/off switch 72, a battery 74,battery charging ports 76 and a relay circuit 78. A preferred electricalcommunication schematic for the operation of the device 10 using theswitch 72, battery 74 and relay circuit 78 is shown in FIG. 3. Thedevice 10 operates on an 8 V system, although any other voltage can beused as well provided that the voltage and current meet design andsafety criteria of the device. The circuit 78 is designed so that amotor circuit 80 is normally in a closed condition, while a solenoidcircuit 82 is normally in a open condition. If the device 10 is set upto operate so that fluid ingress or egress occurs automatically afterrotatory penetration into a tissue site, then the circuit 78 willautomatically open the motor circuit 80 after penetration and close thesolenoid circuit 82. The plunger 46 is either retracted or extendeddepending on the initial state of the shaft of the solenoid via a fluidswitch 83.

Referring to FIG. 2, a second configuration of the device 10 of FIG. 1is shown. The main structural difference between the device of FIG. 1and the device of FIG. 2 is the arrangement of the switch 72, thebattery 74, the battery charger ports and the circuit 78 which arecontained within a pistol grip 84 which extends out substantiallyhorizontally from the housing 12. The grip 84 can be integral with thehousing 12 or can attachably or detachably engage the housing 12. Theswitch 72 is position in a lower surface 86 of the grip 84 so that auser can easily switch the device on and off through finger pressure.

Referring to FIGS. 4 and 5, a third and fourth embodiment of the device,generally 100, of the present invention which are similar to the device10 of FIGS. 1 and 2, respectively, without the inclusion of the motorand bushing/bearing assembly of the device 10. These latter embodimentsare used primarily in procedures where on vertical force is necessaryfor tissue penetration and no rotatory drilling is required. Thecircuitry associated with these latter embodiments is simplified by theabsence of the motor and, thus, the switch 72 can be used to directlyturn on and off the solenoid 50. The device 10 further includes a secondsolenoid 51 to control the rate the depth of penetration of the needle34. The second solenoid 51 is controlled by a on/off second switch 73.

Referring now to FIG. 6, yet another embodiment of tissue penetrationdevice of the present invention, generally 110, includes a three or fourpart detachable construction of the device of FIGS. 1 and 2. The device110 includes a reservoir/needle assembly 112 shown with a male threadedconnection 114 at its proximal end 116. The device 110 also includes asolenoid assembly 118 having a female threaded connection 120 associatedwith its distal end 122 and designed to threadingly engage the maleconnector 114. The solenoid assembly 118 also has a male threadedconnection 124 associated with its proximal end 126 and a rotatory shaftreceiver 128. Of course, the solenoid assembly can be subdivided into asolenoid/needle coupler subassembly which includes the plunger 46, abushing/bearing subassembly and a solenoid subassembly. Thesesubassemblies can be attached by threaded connection, snap connectionsor any other attachment mechanism. Additionally, the devices of thepresent invention can include one or more solenoid where the othersolenoid can be associated with the needle for controlled tissuepenetration.

The device 110 also includes a motor assembly 134 which includes themotor and a female threaded connection 136 associated with its distalend 138 and designed to threadingly engage the male connector 124 and amale threaded connection 140 associated with its proximal end 142 and arotatory shaft 141. The device finally includes a battery assembly 144having a female threaded connection 146 associated with its distal end148 and designed to threadingly engage the male connector 140. Ofcourse, the battery assembly 144 includes the battery, the switch andthe relay circuit and can be vertically disposed or positioned orhorizontally disposed or positioned relative to the other assemblies toproduce the assembled devices depicted in FIGS. 1–2 or 4–5 depending onthe desired subassemblies to be associated with the final device.

Although the assemblies shown in FIG. 6 are connected by threadedconnections and modularized in the manner shown, the device of thepresent invention can be modularized in any other procedure and themodular components can be connected by any other connection means knownin the art such as quick connects, threaded locking connections, snap-onconnections, permanent or removable adhesive bonding, or any othermethod of connecting modular sections together.

Referring now to FIGS. 7–11, a first embodiment of a new tissuepenetrator or needle, generally 200, is shown. The penetrator 200includes a substantially cylindrical hollow tube 202 having a proximalend 204 and a tip 206 associated with its distal end 208. The needle 200also includes two apertures or perforations 210 so that an interior 212of the tube 202 can be brought into fluid communication with a tissuesite through the apertures 210. The tip 206 is paddle shaped having aV-shaped profile as viewed from the front (FIG. 7) and a tapered V-shapewhen view from the side (FIG. 8). The tip 206 has two cutting edges 214and preferably has two raised portions 216 where the tip 206 and thetube 202 transition one into the other and an aperture 215 located at ornear its apex.

As shown FIG. 9, the tip 206 is in the shade of a parallelogram withcutting surfaces 218 associated with a smaller pair of sides 220 andnon-cutting surfaces 222 associated with a larger pair of sides 224. Thetapered V-shaped configuration of the tip 206 is generally achieved bypressing the tip 206 and then grinding the cutting surfaces 218 so thatthe cutting edges 214 will have a cutting angle 225 which has anespecially preferred value of 70°. The raised portions 216 are designedto ensure that the hole drilled into the bone is of a diameter slightlygreater than the diameter of the outside diameter of the tube 202. Forexample, if the tube 202 has an outside diameter of about 1.27 mm, thenthe diameter of the tip 206 at the raised portions 216 would be about1.50 mm. Of course, all that is really required is that the diameter atthe raised portion 216 be slightly greater than the diameter of the tube202 so that no resistance will accompany further insertion of the needle200 after bone penetration.

Referring now to FIGS. 12–16, a second embodiment of a new needle 200 ofthe present invention can be seen to include the same elements as above,with the addition of a bone seal 226. The bone seal 226 is a flanged outportion of the tube 202 and it located a given distance from theperforations 210. If the entire needle is about 38 mm in height and hasan o.d. of about 1.27 mm and the perforations 210 are relatively closeto the raised portions 216 of the tip 206, then the bone seal 226 ispreferably located about 7 mm above the apertures 210. Of course, theeach location of the seal 226 will depend on the use to which the needlewill be put and the depth of penetration desired. As is shown in FIGS.12 and 13, the tube 202 is shown as two distinct pieces 228 and 230 eachhaving a mating flange 232. The two pieces 228 and 230 can be integrallyformed out of a single piece of material or can be made of out separatepieces of material than have been fixedly attached either by bonding,welding, fusing, fitted or by any other technique known in the artwhereby two pieces can be joined together to form a single piecestructure capable of operating as a single unit.

The tapered V-shaped side view of the tips 206 of the needles of FIGS. 7and 12 can be seen to include at least three different tapering regions234, 236 and 238. The first region 234 is associated with the pressingprocess that formed in the tip into a generally rectangular shape fromthe cylindrical shape of the tube. The second and third regions 236 and238 are associated with the tip forming process and cutting edge formingprocess so that a parallelogram configuration is achieved. Thus, thecutting surfaces of the needle have a tapered V-shape as well.

Although the tip is shown as a parallelogram shape having two opposedcutting surfaces and edges, the present invention also contemplatesother polygonally shaped tips including rectangular with two cuttingsurfaces, pentagons with two or three cutting surfaces, hexagons withthree cutting surfaces, etc. where the sides of the polygons are notequal so that the cutting edges are associated with smaller sides of thepolygonal shape and can have sharp well defined cutting edges.

EXAMPLES

The following examples are included for the sake of completeness ofdisclosure and to illustrate the methods of making the compositions andcomposites of the present invention as well as to present certaincharacteristics of the compositions, but in no way are these examplesincluded for the sake of limiting the scope or teaching of thisdisclosure.

In preliminary experiments using a prototype device of the presentinvention using the new needle configuration, the inventors were able toachieve complete penetration of cortical bone in 100% of the cases in1.3 seconds while the whole process currently takes approximately 2 toabout 2.5 seconds (injection or removal of material). The inventors alsoanalyzed time of full penetration plotted against cortical thickness asshown in FIG. 17. The data shown in FIG. 17 demonstrates the penetrationof bone up to 12.5 mm in thickness can be accomplished in under 2.5. Thedata was shown to have a correlation of y=0.134×+0.716 with a r value of0.664. The mean time was 1.248 for a mean thickness of 3.98. Theexisting prototype demonstrates that the devices of this invention allowfor fast bone penetration and delivery or extraction using a solenoid toaffect delivery into or extraction from a tissue site.

All United States patents, all foreign patents and all articles citedtherein are incorporated herein by reference as if each was incorporatedby reference at the time of introduction. Although the invention hasbeen disclosed with reference to its preferred embodiments, from readingthis description those of skill in the art may appreciate changes andmodification that may be made which do not depart from the scope andspirit of the invention as described above and claimed hereafter.

1. An apparatus comprising: a. a tissue penetrator disposed in a distalportion of the apparatus; b. a solenoid for controlling penetratorpenetration speed and depth; c. a motor adapted to rotate the solenoidand the penetrator, d. a power supply and associated circuitry forsupplying electrical power to the solenoid; e. a switch for starting andstopping the solenoid; f. a housing surrounding the penetrator, thesolenoid and the power supply; and g. a disposable, biased retractableprotector having a septum at its distal end and a bias member, where theprotector is detachably connected to a distal end of the apparatus andprotects a tip of the penetrator and where electric power supplied tothe solenoid allows the penetrator to penetrate a tissue site at acontrolled rate and to a controlled depth.
 2. The apparatus of claims 1,wherein the penetrator comprises a hollow shaft, an aperture and a tiphaving a quadrilateral cross-section, where the quadrilateral includestwo opposed short sides and two opposed long sides and where the shortsides comprise cutting surfaces and long sides comprise non-cuttingsurfaces.
 3. The apparatus of claims 2, wherein the quadrilateral is aparallelogram.
 4. The apparatus of claim 1, wherein the bias memberallows the protector to move relative to the penetrator so that thepenetrator penetrates the septum and extends into the tissue site to thecontrolled depth when the apparatus is in use and to move back afteruse.
 5. The apparatus of claim 1, further comprising: a torque sensoradapted to sensor changes in a motor torque, where the power supplysupplies power to the sensor and the circuitry turns the motor off whena change in torque evidences a transition from hard tissue to softtissue.
 6. An apparatus comprising: a. a housing; b. a solenoid mountedin a middle portion of an interior of the housing; c. a power supply andassociated circuitry mounted in an upper portion of the interior of thehousing and connected to the solenoid for supplying electrical power tothe solenoid; d. a motor mounted in the interior of the housing andconnected to the power supply; e. a torque sensor adapted to sensorchanges in a motor torque, f. a tissue penetrator disposed in a distalportion of the interior of the housing and connected to the solenoid; g.a switch for starting and stopping the solenoid; and h. a disposable,biased retractable protector having a septum at its distal end forprotecting a tip of the penetrator, where electric power supplied by thepower supply to the solenoid in a push mode pushes the penetrator into atissue site including bone at a controlled rate and to a controlleddepth and where electric power supplied by the power supply to thesolenoid in a pull mode pulls the penetrator from the tissue site at acontrolled rate, and where electric power supplied by the power supplyto the motor and the circuitry controls a motor speed and a motordirection, and where electrical power supplied to the torque sensor andthe circuitry turns the motor off when a change in torque evidences atransition from bone to soft tissue.
 7. The apparatus of claim 6,wherein the bias member allows the protector to move relative to thepenetrator so that the penetrator penetrates the septum and extends intothe tissue site to the controlled depth when the apparatus is in use andto move back after use.
 8. The apparatus of claim 6, wherein the tissuesite comprises a cranium.
 9. The apparatus of claims 6, wherein thepenetrator comprises a hollow shaft, an aperture and a tip having aquadrilateral cross-section, where the quadrilateral includes two shortsides and two long sides disposed in an alternating configuration sothat the short sides and longs sides are opposed and where the shortsides include cutting surfaces and long sides are non-cutting surfaces.10. The apparatus of claims 9, wherein the quadrilateral is aparallelogram.
 11. An apparatus comprising: a. a housing; b. a powersupply and associated circuitry mounted in an upper portion of theinterior of the housing; c. a motor mounted in the interior of thehousing and connected to the power supply; d. a torque sensor adapted tosensor chances in a motor torque, e. a solenoid mounted in the interiorof the housing and connected to the power supply; f. a tissue penetratordisposed in a bottom portion of the interior of the housing; g. a switchfor starting and stopping the motor and the solenoid; and h. adisposable, biased retractable protector having a septum at its distalend for protecting a tip of the penetrator, where electric powersupplied by the power supply to the motor rotates the penetator at acontrolled rate either in a cutting direction or a retracting directionand where electric power suppled by the power supply to the solenoid ina push mode pushes the penetrator into a tissue site including bone at acontrolled rate and to a controlled depth while the motor rotates thepenetator in the cutting direction and where electric power supplied bythe power supply to the solenoid in a pull mode pulls the penetratorfrom the tissue site at a controlled rate while the motor rotates thepenetator in the retracting direction, and where the electrical powersupplied to the torque sensor and the circuitry turns the motor off whena change in torque evidences a transition from bone to soft tissue. 12.The apparatus of claim 11, wherein the bias member allows the protectorto move relative to the penetrator so that the penetrator penetrates theseptum and extends into the tissue site to the controlled depth when theapparatus is in use and to move back after use.
 13. The apparatus ofclaim 11, wherein the tissue site comprises a cranium.
 14. The apparatusof claims 11, wherein the penetrator comprises a hollow shaft, anaperture and a tip having a quadrilateral cross-section, where thequadrilateral includes two short sides and two long sides disposed in analternating configuration so that the short sides and longs sides areopposed and where the short sides include cutting surfaces and longsides are non-cutting surfaces.
 15. The apparatus of claims 14, whereinthe quadrilateral is a parallelogram.
 16. The apparatus of claim 11,wherein the bias member allows the protector to move relative to thepenetrator so that the penetrator penetrates the septum and extends intothe tissue site to the controlled depth when the apparatus is in use andto move back after use.
 17. The apparatus of claim 11, wherein thetissue site comprises a cranium.
 18. The apparatus of claims 11, whereinthe penetrator comprises a hollow shaft, an aperture and a tip having aquadrilateral cross-section, where the quadrilateral includes two shortsides and two long sides disposed in an alternating configuration sothat the short sides and longs sides are opposed and where the shortsides include cutting surfaces and long sides are non-cutting surfaces.19. The apparatus of claims 18, wherein the quadrilateral is aparallelogram.
 20. An apparatus comprising: a. a tissue penetratordisposed in a distal portion of the apparatus; b. a solenoid forcontrolling penetrator penetration speed and depth; c. a motor adaptedto rotate the solenoid and the penetrator, d. a torque sensor adapted tosensor changes in a motor torque, e. a power supply and associatedcircuitry for supplying electrical power to the solenoid; f. a switchfor starting and stopping the solenoid; g. a housing surrounding thepenetrator, the solenoid and the power supply; and h. a disposable,biased retractable protector having a septum at its distal end and abias member, where the protector is detachably connected to a distal endof the apparatus and protects a tip of the penetrator, and where theelectrical power supplied to the solenoid allows the apparatus topenetrate a tissue site including bone at a controlled rate and to acontrolled depth, and where the electrical power supplied to the motorand the circuitry controls a motor speed and a motor direction, andwhere the electrical power supplied to the torque sensor and thecircuitry turns the motor off when a change in torque evidences atransition from bone to soft tissue.
 21. The apparatus of claim 20,wherein the bias member allows the protector to move relative to thepenetrator so that the penetrator penetrates the septum and extends intothe tissue site to the controlled depth when the apparatus is in use andto move back after use.
 22. The apparatus of claim 20, wherein thetissue site comprises a cranium.
 23. The apparatus of claims 20, whereinthe penetrator comprises a hollow shaft, an aperture and a tip having aquadrilateral cross-section, where the quadrilateral includes two shortsides and two long sides disposed in an alternating configuration sothat the short sides and longs sides are opposed and where the shortsides include cutting surfaces and long sides are non-cutting surfaces.24. The apparatus of claims 23, wherein the quadrilateral is aparallelogram.